1. Field of the Invention
The invention relates generally to electrical enclosures and, more particularly, to electrical enclosures which provide front access to electrical bus members for electrical apparatus housed within the electrical enclosures. The invention also relates to electrical bus assemblies for electrical enclosures.
2. Background Information
A significant goal with regard to power distribution systems in, for example, commercial applications, such as commercial construction applications, is to be cost effective. As such, maintenance and space considerations are driving factors in the design of new electrical equipment. Specifically, the equipment should be easy to maintain in order to minimize the amount of down time required for repair, maintenance, and/or inspection, and it should make the most efficient use possible of the available space (i.e., floor space).
Electrical apparatus, such as, for example, switchgear devices such as medium voltage (about 1,000 volts to about 100,000 volts) circuit breakers, are often housed within an electrical enclosure, such as a switchgear cabinet. Such enclosures have been known to take up substantial floor space. In fact, in some commercial applications, for example, an entirely separate room is allocated just for housing electrical equipment. It will, therefore, be appreciated that there are a number of disadvantages associated with known electrical enclosures. Among them is the fact that they are unnecessarily large in size, and suffer from an ineffective allocation of the interior space within the enclosure. Additionally, many known electrical enclosures are required to be disposed a predetermined distance from adjacent structures, such as, for example, a wall or another piece of electrical equipment. Specifically, the spacing between the electrical enclosure and adjacent structure(s) must be sufficient so as to provide access to the back side of the electrical enclosure where the electrical bus members of the electrical apparatus are typically disposed. These disadvantages contribute to the undesirable inefficient use of a significant amount of valuable floor space.
FIGS. 1A and 1B show a bottom plan view and a side elevational view, respectively, of an example switchgear cabinet 2 having a front 4, a back 6, and first and second sidewalls 8,10. The electrical apparatus 12 that are housed by the switchgear cabinet 2, such as the circuit breakers 14 which are shown, are disposed toward the front 4 of the cabinet 2. The width 11 between first and second sidewalls 8,10 of the example cabinet 2 of FIG. 1A is about 36 inches. Many electrical components such as, for example and without limitation, power cables 16, terminal connections 18 (e.g., without limitation, customer connections), surge arrestors (ARR) 20, main electrical bus 22, and ground busses 24, shown in FIG. 1B, are disposed behind the circuit breakers 14 and are arranged throughout the available space behind the circuit breakers 14 toward the back 6 of the cabinet 2. Thus, these components 16,18,20 and electrical bus members 22,24, many of which require routine inspection, are generally inaccessible except for access provided through the back 6 of the cabinet 2, as previously discussed. Specifically, in order to provide such back access, for example, to enable connection of customer power cables or for inspection, the back 6 of cabinet 2 is required to be spaced a significant distance 25 from other structures such as, for example, the wall 26 shown in FIG. 1A. In the example of FIG. 1A, the distance 25 between the back 6 of the cabinet 2 and wall 26 is about 36 inches. The cabinet 2 also has a depth 28 from front 4 to back 6 of about 96 inches. Accordingly, a significant amount of valuable floor space is undesirably occupied by the cabinet 2, as previously discussed.
Accordingly, the foregoing cabinet configuration disadvantageously requires the cabinet 2 to either be permanently disposed at a location which is sufficiently spaced from adjacent structures (e.g., without limitation, a wall; an adjacent piece of equipment), or to be periodically moved away from the adjacent structure(s) in order to provide access to the back of the cabinet. It is, therefore, desirable to provide an electrical enclosure which allows for adequate inspection of the electrical bus members for electrical apparatus housed within the enclosure, and which can also be permanently disposed adjacent other structures, if desired. It is also desirable to provide an electrical enclosure which is as small as possible, in order to minimize the amount of valuable floor space required for the enclosure.
In an attempt to provide the necessary access to the internal electrical bus members, while permitting the electrical enclosure to be disposed adjacent the wall or other structure, one prior proposal involves the use of one or more side entry removable access panels. However, the access provided by such panels is limited, particularly where a plurality of electrical apparatus (e.g., without limitation, circuit breakers) are mounted laterally adjacent one another within the electrical enclosure. Under such conditions, removable access panels do not provide access to some or all of the electrical bus members and/or to the adjacent circuit breakers which are disposed distal from the access panels, without having to first remove at least some of the electrical bus members which are closest to the access panel.
Other prior proposals have involved the implementation of separate removable or draw-out instrument compartments within the electrical enclosure, or an elaborate telescoping access panel or door to provide limited access through the front of the enclosure. However, removable or draw-out compartment designs are complex and costly, requiring a complicated electrical connector assembly to permit the instrument compartment to be moved into and out of electrical communication with electrical bus members which are permanently disposed within the enclosure. Telescoping or otherwise complicated access panels or doors are also complex and costly, and they disadvantageously take up valuable space within the electrical enclosure which could be more efficiently used in order to reduce the overall size of the enclosure.
There is a need, therefore, for an electrical enclosure which requires minimal floor space while providing sufficient access for the repair, maintenance, and inspection of the electrical bus members for electrical apparatus housed within the enclosure.
There is, therefore, room for improvement in electrical enclosures. There is also room for improvement in electrical bus assemblies for electrical enclosures.